Sail furling devices are known in the art. For example, a roller reefer in U.S. Pat. No. 3,285,215 teaches the reefing of a sail about a boom by rotating the boom and allowing the sail to slide down a retaining means on the mast as its lower end becomes wrapped around the boom. Another method of furling a sail is taught in U.S. Pat. No. 3,332,384 in which the entire mast of a sail boat is rotated thus causing the sail to be wrapped up on the mast. A sail retaining means adapted to use with jib sails is taught in U.S. Pat. No. 3,948,200. This patent teaches a C-shaped groove which grasps the bead along one edge of a jib and allows rapid insertion and removal of a jib sail in the groove and further allows the jib sail to be furled about the rod containing the C-shaped groove. Another sail furling device is shown in U.S. Pat. No. 3,749,042. A sail furling arrangement is taught in U.S. Pat. No. 3,835,804 in which the luff of a sail is attached to a tension member within a hollow mast. When the tension member is rotated, the sail becomes reefed on the tension member within the mast. This arrangement makes no provision for easy removal and replacement of the sail once installed except by complete removal of the tension member.